vhd Files does not shrink after compact

Daniel Doerfel

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Oct 17, 2005, 7:51:08 AM10/17/05

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Hi all,

i have installed Virtual Server 2005 and on it i have run a Virtual PC. The
size of the vhd file ist on the harddisk 8,4 GB. If i now run the Virtual PC
an on the Guest OS i look how big the harddrive ist there are 5,6 GB on use.

Where are the other GB´s?!

If i now run -> Compact on the Inspect VHD on the Admin-Interface of the
VirtualServer Programm the file size of the vhd file does not shrink.

How can i shrink this file without Winzip or something else.

Thanks
Daniel

Paul Adare

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Oct 17, 2005, 8:02:50 AM10/17/05

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In article <OlwnREx0...@TK2MSFTNGP12.phx.gbl>, in the
microsoft.public.virtualserver news group, Daniel Doerfel
<daniel...@msn.com> says...

Make sure that you do the following:

1. Defrag inside of the guest.
2. Run the Virtual Disk Precompactor inside of the guest (mount the ISO,
you can find it in the Virtual Machine Additions folder where you've
installed Virtual Server).
3. Shut down the guest and run compact.

If you've got Ghost or Acronis or something like that, image the VHD to
a new one. You'll get the same level of compaction or better and in my
experience it is faster as well.

--
Paul Adare
MVP - Windows - Virtual Machine
http://www.identit.ca/blogs/paul/
"The English language, complete with irony, satire, and sarcasm, has
survived for centuries without smileys. Only the new crop of modern
computer geeks finds it impossible to detect a joke that is not clearly
labeled as such."
Ray Shea

jdasilva

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Oct 17, 2005, 11:15:39 AM10/17/05

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It appears that Virtual Disk Precompactor is part of Virtual Server 2005
SP1. I was on the MSDN subscriber website and it is not available
there. Is this still in beta? How can I get Virtual Disk
Precompactor?

Jeff

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Paul Adare

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Oct 17, 2005, 12:34:29 PM10/17/05

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In article <jdasilv...@no-mx.forums.yourdomain.com.au>, in the
microsoft.public.virtualserver news group, jdasilva <jdasilva.1x205y@no-
mx.forums.yourdomain.com.au> says...

> It appears that Virtual Disk Precompactor is part of Virtual Server 2005
> SP1. I was on the MSDN subscriber website and it is not available
> there. Is this still in beta? How can I get Virtual Disk
> Precompactor?
>

Download the trial version of VPC2004 which includes SP1 and includes
the precompactor ISO.

JayDubb

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Oct 18, 2005, 7:37:50 PM10/18/05

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Paul, any word if this issue will be fixed in R2? We have quite a few VHDs
that have grown waaaaay beyond their configured size, and on a few servers
(which have smaller 80 GB disks) free space (or the lack thereof) on the host
is getting critical.

Paul Adare

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Oct 19, 2005, 4:02:22 AM10/19/05

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In article <4355874E...@dubb.nowhere.org>, in the
microsoft.public.virtualserver news group, JayDubb
<j...@dubb.nowhere.org> says...

> Paul, any word if this issue will be fixed in R2? We have quite a few VHDs
> that have grown waaaaay beyond their configured size, and on a few servers
> (which have smaller 80 GB disks) free space (or the lack thereof) on the host
> is getting critical.
>

Sorry Jay but which issue are you referring to here?

JayDubb

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Oct 19, 2005, 7:58:02 PM10/19/05

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Sorry.... I'm referring to the issue of actual file size for the vhd growing
way beyond its configured capacity.

When we started using Virtual Server, we (wrongly) assumed a virtual hard
drive created to be X gigabytes in the guest machine would not grow beyond
that size on the host.
Thus, we deployed six VMs with 10GB disks on hosts with 80 GB disks, thinking
6 vhd x 10 GB = 60 GB plus a little for overhead-- more than enough left over
for the host OS to run.

Instead, we're seeing file sizes exceeding 14-16 GB for guests that have a 10
GB vhd. Simple math shows us we can only get FOUR guests per 80 GB host,
rather than six-- a full 33% less guests-per-server density than we bargained
for.

We've had to deploy an additional server with a fat disk for the sole purpose
of relocating VMs whose disks are ougrowing their host's ability to store
them.

I'm having difficulty understanding, if a disk is to hold (say...) no more
than 10 GB of data, why it can grow to more than 140% of that size.

That suggests VS is not efficiently re-claiming disk space that has been freed
by the guest OS-- choosing instead to keep eating away at the host disk while
gigabytes of previously-used-but-now-free VHD space is ignored.

Ben Armstrong [MSFT]

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Oct 19, 2005, 8:06:35 PM10/19/05

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The only time we have seen .VHD files going above their maximum size was
due to customers running Veritas backup agents on the host without
excluding the .VHD files. This is strongly advised against.
--
Cheers,
Benjamin Armstrong
===============================
Virtual machine Program Manager

This posting is provided "AS IS" with no warranties, and confers no rights.
You assume all risk for your use.

JayDubb

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Oct 22, 2005, 10:33:48 AM10/22/05

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Hmmm... we don't use Veritas, but we are seeing the disk overgrowth issue.

Ben Armstrong [MSFT]

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Oct 23, 2005, 1:25:11 AM10/23/05

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Do you have any other backup / defrag / file system level software
running on the host that might be interacting badly?

JayDubb

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Oct 25, 2005, 7:59:55 AM10/25/05

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Just V2i for backups, which copies an image of the disk to a storage array.

Well, more accurately because of network dropouts on VMs during large file
transfers, each guest copies the image to a \\share on the host, and later the
host transfers them to a storage array.

I'm still having difficulty wrapping my brain around why the file system on a
vhd is able to chew away more space than it's allocated. This could never
happen in the physical world...